Authors

Document Type

Report

Publication Date

6-2004

Abstract

Twenty-nine voluntary directed swordfish (Xiphias gladius) pelagic longline sets were conducted in the Windward Passage (n=4) and the southern Gulf of Mexico (n=25) during February-April 2004 aboard the F/V Carol Ann, a U.S.-registered commercial pelagic longline vessel. The goal of this project was to assess differences in catch rate and hooking location between size 16/0 and 18/0 non-offset circle hooks baited with dead squid (Illex sp.) or mackerel (Scomber scomber). Protocols were similar to those developed by Dr. John Watson et al. of the NOAA Fisheries SEFSC-Pascagoula Laboratory for work with pelagic longline vessels in the northern Gulf of Mexico targeting tuna, although modified for the southern Gulf directed swordfish fishery.Catch rates of the size 18/0 circle hooks were lower, but non-significant, in both locations than those of 16/0 hooks when using squid bait, although higher, but also non-significant, catch rates were noted with sets testing these hook combinations with mackerel. Trends in catches suggest that the non-significance of the results may reflect the low statistical power resulting from small sample sizes rather than a lack of relationship. Combined swordfish mortality at haulback for both hook types was relatively low, possibly a consequence of the fact that 51.2% of these swordfish were hooked in the corner of the mouth. Mortality rates at haulback also varied by species and fishing location.